Surge Analysis In Typical Working Conditions Of Zhoushan LNG Receiving Station Shipping Line System

LNG terminal station,which is a station for receiving,storing,vaporizing,and transporting LNG shipped by LNG carrier,is mainly receives and storages LNG,which's standard boiling point is about 162?.Due to the nature of LNG flammable and explosive.As a high quality energy,LNG can bring convenience for people,but we shouldn't ignore the risk of LNG.Throughout the LNG terminal station,ship loading piping system is the area most easily occur accidents.Ship loading piping system easily occurs surge accidents caused by velocity.After these surge accidents,there will cause pipe shocking and pressure rising,which will cause fatiue damage of piping system,even explosion,and cause great harm.Therefore,between the construction process of the LNG terminal station,researching the safety and reliability of LNG piping system is significant.This paper mainly studys the ship loading piping system of an LNG terminal station,and bases on the hydraulic transient flow analysis theory,and models for the piping system by applying related engineering software,and determines the most unfavorable conditions,through the analysis of the structure and operation conditions of this piping system.On the basis of analyzing the calculation results of the most unfavorable conditions,and providing operation guidance and optimization to the topology result of the piping system.First,this paper analyzes the mature surge analysis analysis software intra-industry,and determines using AFT Impulse for analysis,by comparing the software.Secondly,this paper analyzes the transient air pockets model in the software,by analyzing the steady-state and transient mathematical model and solving algorithm.Then,this paper determines input boundary conditions and initial conditions in AFT Impulse,which include the physical parameters' choice of LNG,and parameters of ship loading pumps,pipes,valves etc.,by analyzing the ship loading piping system of LNG terminal station.Finally,this paper determines conditions of transient state hydraulic calculation,and obtains the results of the steady-state calculation and the transient hydraulic calculation about LNG ship loading piping system by modeling and analyzing the process.Through the analysis of the results,a set of feasible analysis method about LNG ship loading piping system is obtained.Surge analysis results show that the surge pressure waves within the scope of the reasonable design pressure,and the maximum transient pressure safety checking meets the requirements under the selected adverse operating conditions.